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The effect of electron cyclotron heating (ECH) and current drive (ECCD) on energetic-particle (EP)-driven magnetohydrodynamic (MHD) modes is studied in the helical devices LHD, TJ-II and Heliotron J. We demonstrate that EP-driven MHD modes, including Alfvén eigenmodes (AEs) and energetic particle modes (EPMs), can be controlled by ECH/ECCD. In the LHD device, which has a moderate rotational transform and a high magnetic shear, co-ECCD enhances toroidal AEs (TAEs) and global AEs (GAEs), while counter-ECCD stabilizes them, which improves the neutron rate compared with the co-ECCD case. Counter-ECCD decreases the core rotational transform and increases the magnetic shear, strengthening the continuum damping on the shear Alfvén continua (SAC). In the TJ-II device, which has a high rotational transform, moderate magnetic shear and low toroidal field period, helical AEs (HAEs) appear when the HAE frequency gap of the SAC is changed by counter-ECCD combined with a bootstrap current and NB-driven current. On the other hand, both co- and counter-ECCD are effective in stabilizing GAEs and EPMs in the Heliotron J device, which has a low rotational transform and low magnetic shear. The experimental results indicate that the magnetic shear has a stabilizing effect regardless of its sign. Modelling analysis using the FAR3d code shows that the growth rates are reduced by both co- and counter-ECCD in Heliotron J, reproducing the show that the effect depends on the magnetic configuration. In Heliotron J, some modes are stabilized experimental results. ECH only also affects EP-driven MHD modes, and the experimental results with an increase in ECH power in the low-bumpiness magnetic configuration, while some modes are destabilized in the high- and medium-bumpiness magnetic configurations.

This paper reports about a novel approach to the absolute intensity calibration of an electron cyclotron emission (ECE) spectroscopy system. Typically, an ECE radiometer consists of tens of separated frequency channels corresponding to different plasma locations. An absolute calibration of the overall diagnostic including near plasma optics and transmission line is achieved with blackbody sources at LN2 temperature and room temperature via a hot/cold calibration mirror unit. As the thermal emission of the calibration source is typically a few thousand times lower than the receiver noise temperature, coherent averaging over several hours is required to get a sufficient signal to noise ratio. A forward model suitable for any radiometer calibration using the hot/cold method and a periodic switch between them has been developed and used to extract the voltage difference between the hot and cold temperature source via Bayesian analysis. In contrast to the classical analysis which evaluates only the reference temperatures, the forward model takes into account intermediate effective temperatures caused by the finite beam width and thus uses all available data optimally. This allows the evaluation of weak channels where a classical analysis would not be feasible, is statistically rigorous, and provides a measurement of the beam width. By using a variance scaling factor, a model sensitive adaptation of the absolute uncertainties can be implemented, which will be used for the combined diagnostic Bayesian modeling analysis.

Heat and particle losses in magnetically confined fusion devices are dominated by anomalous losses that are thought to be driven by micro-turbulence. Micro-turbulence contributes to the inverse cascade of energy from small-scale fluctuations to large-scale turbulent eddies, which serves to increase the level of particle and thermal loss observed in experiments. The transport of heat and particles from fusion devices is one of the greatest hurdles to magnetically confined fusion as an energy source, and understanding anomalous transport would contribute significantly to developing a fusion reactor. Transport in plasma physics is commonly characterized as classical/neoclassical or anomalous. Classical diffusive transport is an irreducible floor to transport caused by collisions in homogeneous fields, and neoclassical transport is the enhancement over classical transport by magnetic field inhomogeneity. Anomalous transport is the transport not described by neoclassical theory. The sourcing of fuel and the removal of impurities in a fusion reactor depends on particle transport, while the size of the reactor is primarily driven by thermal transport making accurate predictions of transport necessary for fusion experiments. There are two fusion experiments under construction in Europe that will be greatly affected by anomalous transport: ITER and W7-X. These two experiments are thought to be the intermediary step necessary for a demonstration fusion reactor of their respective configurations. ITER represents the tokamak configuration, and W7-X represents an optimized stellarator configuration. These two forms of magnetic confinement devices are differentiated by their confining magnetic field. Each is topologically a torus, but the confining magnetic field of the tokamak is partially generated by an inductively driven current, while the confining field of the stellarator is entirely generated by external coils. Transport in each configuration is dominated by anomalous transport, but their fundamental differences allow that transport to be studied. Heat pulse propagation experiments can be used to measure thermal transport. 1D simulations of modulated heating and the resulting heat pulses have been completed for the Helically Symmetric eXperiment (HSX). A spatially localized, modulated plasma heating source and an electron temperature diagnostic with sufficient temporal resolution are necessary to perform heat pulse propagation experiments. Simulation results are reported in Chapter 2, and the interpretation of heat pulse propagation simulations is described in Sections 2.1 and 2.1.2. The installation of a modulatable Electron Cyclotron Resonant Heating (ECRH) system is described in Section 3.1, and the upgrade and analysis of the Electron Cyclotron Emission (ECE) diagnostic on HSX is described in Sections 3.2 and 3.3.

Bibliography: leaves 228-237.